batati vaŽno

8/4/2019 BATATI VANO

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Rambutan

Saichol Ketsa1 and Robert E. Paull21Department of Horticulture, Kasetsart University, Bangkok, Thailand2

Department of Tropical Plant and Soil Sciences, University of Hawaii at Manoa, Honolulu, HI

Scientific Name and Introduction: Rambutan fruit (Nephelium lappacium L.) are large ovoid orglobose fruit about 4.5 cm (1.8 in) long and 2.5 to 3.7 cm (1 to 1.5 in) wide that occur on woody stalks inclusters of 10 to 18. The outer skin is 2 to 4 mm (0.1 to 0.2 in) thick and covered with soft, long spines(spinterns) that turn red or yellow when ripe. The edible aril flesh is attached to a single, large seed. Thefruit is related to litchi and longan (Nakasone and Paull, 1998).

Quality Characteristics and Criteria: Quality criteria include: fruit size, shape, and weight; bright skinand spine color; uniformity; absence of defects; and freedom from disease and insects. High SSC andlow TA are desirable (Ketsa and Klaewkasetkorn, 1992). Mechanical injury and dehydration are majorcauses of appearance loss.

Horticultural Maturity Indices: Skin and spine coloration is the main horticultural maturity index.Fruit having green skin and greenish-red spines are sour. Fruit have both skin and spines red or yellow,depending upon variety. Between these two stages, sugar content increases about 20%, and acid levelsare half that at the green stage (Mendoza et al., 1982). The acceptable stage is 16 to 28 days after colorbreak, at which time skin and spines are brightly colored (OHare, 1992). Over-ripe fruit have a waterytexture (Somboon, 1984) which may be a senescence-induced tissue breakdown.

Grades, Sizes and Packaging: There are no U.S. or International grade standards. Fruit are sold in 2.25kg (5 lb) and 4.5 kg (10 lb), one-piece, fiberboard cartons. Sometimes fruit are pre-packed in punnets.In Southeast Asia, clusters of fruit are sold in bunches still attached to the stem

Pre-cooling Conditions: Only room-cooling is recommended.

Optimum Storage Conditions: Store at 8 to 15 C (46 to 59 F) with 90 to 95% RH to achieve astorage-life of 14 to 16 days. There may be changes in the skin and spine coloration after storage, but theflesh is unaffected. Temperature recommendations vary for different cultivars (OHare, 1992). Fruitheld at 20 C (68 F) with 60% RH last about 3 to 5 days.

Controlled Atmospheres (CA) Consideration: CA of 7 to 12% CO2 + 3 to 5% O2 at 10 C (50 F) isrecommended (Kader, 1993). At 9 to 12% CO2 color loss is reduced and shelf-life extended by 4 to 5days, while low O2 (3%) has little affect (OHare et al., 1994; OHare, 1995). CO2 levels >12% have noadditional effect, and decay can begin after a few weeks storage. The MA/CA effect appears to be morevia CO2 elevation and minimizing water loss than through effect of low O2. Storage in sealedpolyethylene film bags or plastic containers is effective in reducing water loss (Mendoza et al., 1972;Ketsa and Klaewkasetkorn, 1995; Mohamed and Othman, 1988), while wax coatings are less effective(Mendoza et al., 1972; Brown and Wilson, 1988; Lam and Ng, 1982). A shelf-life of 14 to 21 days canbe expected.

Retail Outlet Display Considerations: Display preferably in trays with a clear film over-wrap or inclam shell containers with no perforations at 10 to 12 C (50 to 55 F). Do not mist or ice.

Chilling Sensitivity: If maintained at 5 C (41 F), fruit can be stored for up to 3 weeks, but the skinand spines change from red to brownish-red; the edible aril is white and remains in good condition (Lam


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and Ng, 1982). Somboon (1984) reported that after 3 days at 5 C (41 F), the aril turned from white(translucent) to being more transparent and juicier.

Ethylene Production and Sensitivity: This non-climactic fruit has a very low rate of ethyleneproduction at < 0.04 L kg-1 h-1 (OHare et al., 1994). Higher rates of up to 3 L kg-1 h-1 can occur, ifthere is a fungal infection. The presence of 5 L L-1 ethylene in CA (9 to 12% CO2) or the presence of an

ethylene absorber does not influence rate of skin color loss (OHare, 1995).

Respiration Rates: Respiration is 40 to 100 mg (about 23 to 57 L) CO2 kg-1 h-1 at 25 C (77 F).

This is a non-climacteric fruit and the rates are for mature fruit; immature fruit respiration rates are higher(Mendoza et al., 1972). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton perday or by 61 to get kcal per metric ton per day.

Physiological Disorders: Chilling injury and darkening of spines and skin are major postharvestdisorders. Darkening is due to dehydration and mechanical injury (Landrigan et al., 1996). Pre-harvestdisorders include skin splitting and poor filling of fruit (OHare, 1992). Skin splitting occurs in thinskinned cultivars often following heavy rains during the last phase of fruit growth. Poor filling has beenassociated with poor nutrition and dry conditions just after flowering.

Postharvest Pathology: Postharvest losses due to disease are low (Ketsa and Klaewkasetkorn, 1992),though stem end rot and fruit rots are found. Sangchote et al. (1992) found that the spectrum of fungiassociated with rambutan decay varied with storage temperatures. Collectotrichum gloeosporioides andBotryodiplodia theobromae are considered the most serious pathogens. Other pathogens recordedincludePestalotiopsis spp. andPhomopsis spp. (Farungasang et al., 1991).

Quarantine Issues: Rambutan is a fruit fly host, and the available treatments are irradiation and heattreatment. Heat treatment leads to rapid loss of skin color. Mealy bugs are often found on the fruit, butno damage to the flesh occurs (Ketsa and Klaewkasetkorn, 1992).

Suitability as Fresh-cut Product: Limited, since it is difficult to separate the aril and seed.

Special Considerations: None.

References:Brown, B.I. and P.R. Wilson. 1988. Exploratory study of postharvest treatments on rambutan

(Nephelium lappaceum) 1986/1987 season. Rare Fruit Counc Austral. Newsletter 48:16-18.Farungoang, U., N. Farungsang and S. Sangchote. 1991. Postharvest diseases of rambutan during storage

at 13 or 25 C. 8yh Austral. Plant Pathol. Soc. Congr., Sydney, Australia (abstract)Kader, A.A. 1993. Modified and controlled atmosphere storage of tropical fruits. In: B.R. Champ, E.

Highley and G.I. Johnson (eds) Postharvest handling of tropical fruits. Proc. Intern. Confer. ChiangMai, Thailand, July 1993, ACIAR Pub. No. 50, pp 239-249.

Ketsa, S. and O. Klaewkasetkorn. 1992. Postharvest quality and losses of Rongrein rambutan fruits inwholesale markets. Acta Hort. 321:771-777.

Ketsa, S. and O. Klaewkasetkoan. 1995. Effect of modified atmosphere on chilling injury and storage-lifeof rambutan. Acta Hort. 398:223-231.

Lam, P.F. and K.H. Ng. 1982. Storage of waxed and unwaxed rambutan in perforated and sealedpolyethylene bags. MARDI Food Technol. Div. Rpt. No. 251, 23 pp.

Landrigan, M., S.C. Morris, D. Eamus and W.B. McGlasson. 1996. Postharvest water relationships andtissue browning of rambutan fruits. Sci. Hort. 66:201-208.

Mendoza, D.B., E.B. Pantastico and F.B. Javier. 1972. Storage and handling of rambutan (Nepheliumlappaceum L.). The Philippines Agriculturist 55:322-332.

Mendoza, D.B., P.T. Ramos, G.R. del Mundo, N.L. Garcia and G.G. Bantoc. 1982. Maturity and


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ripening guide for rambutan cultivars. ASEAN-PHTRC Tech. Bull. No. 5. Univ. Philippines LosBanos.

Mohamed, S. and E. Othman. 1988. Effect of packaging and modified atmosphere on the shelf- life oframbutan (Nephelium lappaceum). Pertanika 11:217-228.

Nakasone, H.Y. and R.E. Paull. 1998. Tropical fruits. CAB Intl., Wallingford, U.K. 445 pp.OHare, T.J. 1992. Rambutan: Postharvest physiology and storage. Trop. Fruit News 26:4-6.

OHare, T.J. 1995. Postharvest physiology and storage of rambutan. Postharv. Biol.Technol. 6:189-199.OHare, T.J., A. Prasad and A.W. Cooke. 1994. Low temperature and controlled atmosphere storage of

rambutan. Postharv. Biol. Technol. 4:147-157.Sangchote, S.,U. Farungsang and N. Farungsang. 1992. Rambutan diseases. In: ACIAR Project 8844,

Wkshp Postharv. Hand. Trop. Fruit, July 1992, Bangkok, Thailand. pp. 17.Somboon, Y. 1984. Effect of temperature and maturity stages on biochemical changes during storage of

rambutan (Nephelium lappaceum Linn.) cv. Seechompoo and cv. Rongrien. M.S. Thesis. KasetsartUniversity, Bangkok, Thailand, 64 p. (Thai)


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Raspberry

Penelope Perkins-VeazieSouth Central Agricultural LaboratoryUSDA-ARS, Lane, OK

Scientific Name and Introduction: Raspberries (Rubus ideaus L.) are a member of the Rosaceaefamily, grown as a perennial crop. Raspberries are available commercially in red, yellow, purple, andblack forms. The red or yellow raspberry is classified into two subspecies,R. idaeus subsp. vulgatusArrhen. (European red raspberry) andR. idaeus subsp.strigosus Michx. (American red raspberry). Blackraspberries found in eastern North America areR. occidentalis L.;R. glaucus L. is a South Americantetraploid black raspberry. Purple raspberries (R. neglectus Peck.) result from crosses of black and redraspberries. All commercially important raspberry species are prized for their unique and delicate fruitflavor and are often used in fresh desserts. Berries are compound fruits, made up of many drupelets, anda hollow center where the fruit detaches from the receptacle. Berries are soft, juicy, and with a distinctaroma. Important cultivars include Meeker, Heritage, Tulameen, Willamette, Chilliwack, and Munger.

Quality Characteristics and Criteria: High quality raspberries are free of injury, decay, and sunscald,are uniformly colored, and appear turgid.

Horticultural Maturity Indices: For fresh market, raspberries are best harvested when bright- red (redraspberry) or fully-colored (black, purple, or yellow raspberry). Berries should pull or shake easily fromthe receptacle, yet be firm, not mushy. Color development after harvest is highly cultivar dependent;Heritage berries turn purple-red quickly while Nova retains a full red color. Cultivars known tochange color rapidly are sometimes picked when pink, although acid levels are higher and flavor low orlacking at this color stage.

Grades, Sizes and Packaging: Raspberries are graded as U.S. No.1 or No.2 based on freedom frommold, decay, sunscald, over-ripeness, and injury. A limit of 1% of berries for mold and 10% total fordefects separates No. 1 grade from No. 2. No. 2 fruit can have no more than 2% berries with decay.

Trays holding 12 one-half pints (125 g), usually vented plastic clamshell containers, are the standardpackage. No minimum berry size is required.

Pre-cooling Conditions: Raspberries should be forced-air cooled to 1 C (33.8 F) within 12 h of harvest(Moore and Robbins, 1992).

Optimum Storage Conditions: Raspberries should be held no more than 2 to 5 days, depending oncultivar, at -0.5 to 0 C (31 to 32 F) with > 90% RH.

Controlled Atmosphere (CA) Considerations: Raspberries benefit from 10 to 20% CO2 + 5 to 10% O2(Kader, 1997). CA storage slows respiration, ethylene production, softening, color change, and growthof molds. Levels of CO2 > 20% can cause discoloration, softening, and off-flavor of raspberries (Agarand Streif, 1996).

Retail Outlet Display Conditions: Raspberries should be stored and displayed at the coldestrefrigeration temperature possible without freezing. As little as 1 day at 20 C (68 F) can result ingrowth of Gray Mold (Botrytis cinerea Pers.).

Chilling Sensitivity: Raspberries are not known to be chilling sensitive.

Ethylene Production and Sensitivity: Stimulation ofBotrytis cinerea (gray mold) growth can occur on


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raspberries in the presence of ethylene; also, color can be adversely affected, darkening to a purple-red inred raspberries. Ethylene production is cultivar-dependent, from 1 to 12 L kg-1 h-1 at 20 C (68 F)(Burdon and Sexton, 1990; Perkins-Veazie and Nonnecke, 1992).

Respiration Rates:Temperature mg CO2 kg

-1 h-1

2 C 16 to 184 to 5 C 18 to 2710 C 31 to 3915 to 16 C 28 to 5520 to 21 C 74 to 175

To get mL kg-1 h-1, divide the mg kg-1 h-1 rate by 2.0 at 0 C (32 F), 1.9 at 10 C (50 F), and 1.8 at 20C (68 F). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton per day or by61 to get kcal per metric ton per day. Data are from Haller et al. (1941), Perkins-Veazie and Nonnecke(1992) and Perkins-Veazie (unpublished).

Physiological Disorders: Shriveling (water loss), leakers (berries with leakage of juice), and UV damage(white drupelets) are the primary disorders found in raspberries.

Postharvest Pathology: The most common postharvest diseases are gray mold (Botrytis cinerea Pers.)and Rhizopus rot (Rhizopus stoloniferEhrenb.:Fr.) (Ellis et al., 1991; Jennings, 1988).

Quarantine Issues: None known.

Suitability as Fresh-cut Product: Incorporated into mixed fruit cups.

Special Considerations: Damage easily; one of the most fragile and perishable of all fruits.

References:Agar, I.T. and J. Streif. 1996. Effect of high CO 2 and controlled atmosphere (CA) storage on the fruit

quality of raspberry. Gartenbauwissenschaft 61:261-267.Burdon, J.N. and R. Sexton. 1990. Fruit abscission and ethylene production in red raspberry cultivars.

Sci. Hort. 43:95-102.Ellis, M.A., R.H. Converse, R.N. Williams and B. Williamson (eds) 1991. Compendium of raspberry

and blackberry diseases and insects. APS Press, St. Paul MN.Haller, M.H., D.H. Rose and P.L. Harding. 1941. Studies on the respiration of strawberry and raspberry

fruits. USDA Cir. No. 613, 13 pp.Kader, A.A. 1997. A summary of CA requirements and recommendations for fruits other than apples and

pears. Proc. 7th Intl. Contr. Atmos. Res. Conf., Univ. of Calif. 3:1-34.Moore, P. P. and J. Robbins. 1992. Fruit quality of stored, fresh red raspberries after a delay in pre-

cooling. HortTechnology 2:468-470.Perkins-Veazie, P. and G. Nonnecke. 1992. Physiological changes during ripening of raspberry fruit.

HortScience 27:331-333.

Acknowledgments: Some information included is from the UC-Davis website on Fresh Produce Factsat http://postharvest.ucdavis.edu/produce/producefacts/Fruit/berry.html.
http://postharvest.ucdavis.edu/produce/producefacts/Fruit/berry.htmlhttp://postharvest.ucdavis.edu/produce/producefacts/Fruit/berry.htmlhttp://postharvest.ucdavis.edu/produce/producefacts/Fruit/berry.html


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Rhubarb

Donald N. MaynardUniversity of Florida, Bradenton, FL

Scientific Name and Introduction: Rhubarb or pie plant (Rheum rhabarbarum L.) is a perennialbelonging to the Polygonaceae family. Fleshy petioles are the edible portion. Petioles may be green,pink, or white depending on the variety. Field production in North America is mainly in Washington,Oregon, Michigan and Ontario. Rhubarb is forced in heated structures in Washington, Michigan andOntario. Fresh rhubarb is mostly available in late Winter through Spring (Foust and Marshall, 1991), butlimited supplies are available at other times.

Quality Characteristics and Criteria: Petiole color is associated with rhubarb quality. The order ofpreference is red, pink, and green. Petioles should appear fresh with no signs of desiccation or decaywhether presented for sale intact or cut into sections.

Grades, Sizes and Packaging: U.S. grades for field-grown rhubarb include U.S. Fancy, U.S. No. 1,U.S. No. 2 and Unclassified (Anon, 1966). They are based primarily on petiole color, frequency of

defects, and appearance. State and provincial grades have been developed for forced rhubarb. Forexample, Washington rhubarb is marketed as Fancy and Extra Fancy (McGregor, 1987) while Michiganrhubarb is classed as Choice, Small Fancy and Fancy (Pennell, 1976). Rhubarb is packed in 4.5, 6.8, or9.0 kg (10, 15, or 20 lb) cartons (Anon, 1995).

Pre-cooling Conditions: Rhubarb petioles should be pre-cooled to 0 C (32 F) by hydro-cooling orforced-air cooling (McGregor, 1987).

Optimum Storage Conditions: Rhubarb petioles can be stored for 2 to 4 weeks at 0 C (32 F) with 95to 100% RH (McGregor, 1987).

Controlled Atmosphere Considerations: CA storage has not yet been used for rhubarb.


-1 h-1

0 C 9 to 135 C 11 to 1810 C 2515 C 31 to 4820 C 40 to 57

To get mL kg-1 h-1, divide the mg kg-1 h-1 rate by 2.0 at 0 C (32 F), 1.9 at 10 C (50 F), and 1.8 at 20C (68 F). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton per day or by61 to get kcal per metric ton per day.

Physiological Disorders: Petioles lacking small leaf lamina are subject to splitting when exposed tomoisture. Over-mature petioles become pithy. Abrasion of petioles by sand or rough handling adverselyaffects appearance.

Postharvest Pathology: Several diseases may cause postharvest losses of rhubarb (Snowdon, 1992).Anthracnose (Colletotrichum erumpens) causes oval, soft, watery lesions on petioles. Bacterial soft rot(Pseudomonas marginalis, Erwinia caratovra) causes a soft, slimy decay. Gray Mold (Botrytis cinerea)causes soft, brown lesions on petioles. Postharvest decay is usually traced to poor sanitation of hydro-cooling water, so proper sanitation with recommended storage temperature is essential to avoid infection.


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Quarantine Issues: None.

Suitability as Fresh-cut Product: Not yet evaluated.

References:

Anonymous. 1966. United States standards for grades of rhubarb (field grown). USDA, Washington,DC.

Anonymous. 1995. The PACKER Sourcebook. Vance Publishing Co., Lenexa KS.Faust, C.M. and D.E. Marshall. 1991. Culinary rhubarb production in North America: History and recent

statistics. HortScience 26:1360-1363.McGregor, B.M. 1987. Tropical products handbook. USDA Agric. Handbook No. 668.Pennell, J.T. 1976. Rhubarb production. USDA Leaflet No. 555.Snowdon, A.L. 1992. Color atlas of postharvest diseases and disorders of fruits and vegetables. Vol. 2,

Vegetables. CRC Press, Boca Raton, FL.


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Rutabaga

Maria Cecilia do Nascimento NunesDepartment of Soils and Agrifood EngineeringLaval University, Quebec, Canada

Scientific Name and Introduction: Rutabaga (Brassica napus L.; Napobrassica group), also referred asswedes, Swedish turnips, and turnip-rooted cabbage, is a member of the Cruciferae. The edible portion isthe large, usually yellow-fleshed storage root. The three main commercial varieties of rutabagas includeAmerican Purple Top, Laurentian, and the Thomson Strain of Laurentian. Rutabaga is a cool seasonvegetable that withstands frost and mild freezing. In North America, rutabaga is primarily grown inCanada, California, Colorado, Wisconsin and Minnesota.

Quality Characteristics and Criteria: A high quality rutabaga is a well-shaped, purple-top root thathas a smooth, small neck, and a well-defined taproot with a minimum of side roots, and is free ofblemishes and bruises. The roots should be firm, fresh looking, sweet and not bitter, and heavy for theirsize. Lightweight rutabagas may be woody (Gardner and Nonnecke, 1987).

Horticultural Maturity Indices: Rutabagas should be harvested when fully mature, since immaturerutabagas can have a bitter taste. Good quality rutabagas are harvested when maximum sugaraccumulation has occurred. Winter crops should be harvested before weather becomes hot, or rootsbecome pithy and woody. Harvesting Fall crops after the first frost can sweeten flavor (Suzuchi andCutcliffe, 1981).

Grades, Sizes and Packaging: Grades include U.S. No. 1 and U.S. No. 2, based on subjective externalappearance. Sizes are defined as Small, (diameter of 5.1 to10.2 cm; 2 to 4 in); Small-Medium (8.9 to 14cm; 3.5 to 5.5 in); Medium (10.2 to 15.2 cm; 4 to 6 in); and Large (13 to 17.8 cm; 5 to 7 in). Commonpackaging is 23 kg (50 lb) bushel cartons or bags (about 20 roots) and 11 kg (25 lb) 0.5-bushel cartons(about 10 roots).

Pre-cooling Conditions: Roots should be cooled as quickly as possible in order to avoid excessivemoisture loss. Brown surface discoloration called storage burn can be largely controlled by rapidcooling at 0 C (32 F) together with adequate air circulation (Franklin and Lougheed, 1975). Ifharvested when the soil or air is above 25 C (77 F), they should be cooled within 3 to 4 h to avoid lossof quality during storage. Room-cooling is most commonly used, however, forced-air cooling, hydro-cooling and package-icing can also be used to retard development of skin discoloration, weight loss anddecay.

Optimum Storage Conditions: Rutabagas can be kept for 4 to 6 mo at 0 C (32 F) with 98 to 100%RH (van den Berg and Lentz, 1973). They should be stored unwrapped, in a cool, moist, dark area withgood ventilation. If held 6 mo at 2 C (36 F) with 95% RH or 5 C (41 F) with 90% RH, weight losscan be as high as 6 and 11%, respectively (Cutcliffe and Anderson, 1989). Rutabagas for immediatemarketing are often waxed to enhance appearance and protect against excessive moisture loss. Waxedroots will keep well under refrigerated conditions for 1 to 2 mo. Roots for long-term storage should notbe waxed, since wax coatings become unsightly during storage and it may impede adequate gasexchange.

Controlled Atmosphere (CA) Considerations: There are no indications that rutabagas stored in CAhave superior quality or longer shelf-life than roots stored at normal atmosphere at 0 C (32 F) with highRH (Franklin and Lougheed, 1975; Tomkins, 1959). Furthermore, CO2 > 8% is injurious to rutabagas.


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Retail Outlet Display Considerations: Rutabagas should be held in a refrigerated display. Use of topice is accepted; misting is not recommended.

Chilling Sensitivity: Rutabagas are not sensitive to chilling, and should be stored as cold as possible.They can stand slight freezing without injury.

Ethylene Production and Sensitivity: Rutabagas produce very low amounts of ethylene at < 0.1 L kg-

1 h-1 at 20 C (68 F), and exposure to ethylene is not an important factor.


-1 h-1

0 C 4 to 65 C 8 to 1210 C 9.5 to 1915 C 20 to 3120 C 34 to 40

To get mL kg-1 h-1, divide the mg kg-1 h-1 rate by 2.0 at 0 C (32 F), 1.9 at 10 C (50 F), and 1.8 at 20C (68 F). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton per day or by61 to get kcal per metric ton per day. Data are from the International Institute of Refrigeration (1967).

Physiological Disorders: Rutabagas freeze at about -1 C (30 F), and freezing may be initiated at -0.5C (31 F). Symptoms include small, water-soaked spots on the surface and light browning of the flesh.Injured tissue appears tan or gray and gives off a fermented odor.

Brown heart or water-core of rutabagas is due to boron deficiency. Stored roots with brown heartmay suffer tissue breakdown and moisture loss, thus becoming spongy; they may also develop brownspots and cracks (Ryall and Lipton, 1983).

Postharvest Pathology: Rot diseases are promoted by storage at higher than recommendedtemperatures. Brown soft rot caused byBotrytis cinerea is a major pathogen. Mold growth typicallybegan at sites of tissue damage and then spreads to adjacent roots creating a dense surface growth of

mycelium and conidia. Black rot caused byPhoma lingam causes restricted dry, corky, dark brown orblackish lesions with a sparse superficial growth of white mycelium. Phoma lesions can occur both atcut surfaces, where discoloration frequently spread into the vascular tissue, and as small craters onundamaged skin (Geeson et al., 1989). Bacterial soft rot caused byErwinia carotovora has also beenassociated with postharvest deterioration of roots during storage (Shattuck and Proudfoot, 1990).

Quarantine Issues: Rutabagas must be completely free of soil because many plant pests are soil-borne.A Permit to Import rutabagas into Canada is required for areas of New York State (because of thepossible presence of Golden Nematode,Heterodera rostochiensis), off-continent U.S. and all othercountries.

Suitability as Fresh-cut Product: Rutabagas are good candidates for sale in consumer size packages.Pre-peeled rutabagas packaged in consumer film bags keep in good conditions for 3 weeks at 0 C (32F). Fresh-cut rutabagas stored in 15% O2 will keep for 10 days at 10 C (50 F) and 20 days at 1 C (34F). Fermentation may occur at lower O2 (Alexander and Francis, 1964).

Special Considerations: Strong odors may be transferred to fruits and leafy vegetables if they are heldin the same storage area with rutabagas.

References:Alexander, B. and F.J. Francis. 1964. Packaging and storage of pre-peeled rutabagas. Proc. Amer. Soc.


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Hort. Sci. 85:457-464.Cutcliffe, J.A. and J.B. Anderson. 1989. Effects of added nitrogen and potassium on yield and storability

of rutabagas. Can. J. Plant Sci. 69:1359-1363.Franklin, E.W. and E.C. Lougheed. 1975. Storing Rutabagas. Ministry of Agriculture and Food Ontario,

Factsheet No. 75-068, AGDEX 258/64.Gardner, J. and I.L. Nonnecke. 1987. Rutabagas (Table turnips). Ministry of Agriculture and Food

Ontario, Factsheet No. 87-032, AGDEX 258/20.Geeson, J.D., K.M. Browne and H.P. Everson. 1989. Long-term refrigerated storage of swedes. J. Hort.

Sci. 64(4): 479-483.Intern. Inst. Refrig. 1967. Recommended conditions for cold storage of perishable produce, 2nd Edition.

International Institute of Refrigeration, Paris.Ryall, A.L. and W.J. Lipton. 1983. Handling, transportation and storage of fruits and vegetables. Vol. 1,

2nd Ed. Vegetables and melons. AVI, Westport, Conn.Shattuck, V.I. and K.G. Proudfoot. 1990. Rutabaga breeding. Plant Breeding Rev. 8:217-248.Suzuki, M. and J.A. Cutcliffe. 1981. Sugars and eating quality of rutabagas. Can. J. Plant Sci. 61: 167-

169.The Packer. 1997. Produce Availability and Merchandising Guide.Tomkins, R.G. 1959. The biological effects of sealed plastic containers by prepacked fresh fruit and

vegetables. Bull. Int. Inst. Refrig. 40:Annex 3.Van den Berg, L. and C.P. Lentz. 1973. High humidity storage of carrots, parsnips, rutabagas, and

cabbage. J. Amer. Soc. Hort. Sci. 98(2): 129-132.

Acknowledgements: Some of the information included was from the Agriculture Canada-Canadian FoodInspection Agency website at http://www.cfia-acia.agr.ca, the USDA-APHIS, Plant Protection andQuarantine website at http://www.aphis.usda.gov/ppq/, and the USDA-Agricultural Marketing Servicewebsite at http://www.ams.usda.gov/standards/.
http://www.cfia-acia.agr.ca/http://www.aphis.usda.gov/ppq/http://www.ams.usda.gov/standards/http://www.cfia-acia.agr.ca/http://www.aphis.usda.gov/ppq/http://www.ams.usda.gov/standards/


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Salad Greens

Kimberly P. WrightDole Fresh Vegetables, Salinas, CA

Scientific Names and Introduction: Various greens other than lettuces are used in raw salads. Theseinclude, but are not limited to: corn salad; lambs lettuce; field salad; mche Valerianella locusta (L.)Latterrade em. Betcke (V. olitoria); dandelion Taraxacum officinale Wiggers; French or round sorrelRumex scutatus; Garden sorrel R. acetosa L; Miners lettuce; Winter purslane; claytonia Montiaperfoliata (Claytonia perfoliata); Mizuna Brassica rapa L. subsp.japonica (Group Japonica); purslanePortulaca oleracea L.; and Rocket salad, roquette, arugula, rucola, rugulaEruca vesicaria (L.) Cav.subsp.sativa (Mill.) Thell. Young leaves are generally used. For other salad vegetables, see watercress,chicory, beet greens, chard, kale, mustard and turnip greens, and Asian brassicas such as red Chinesemustard, tat soi, and napa cabbage.

Quality Characteristics and Criteria: Greens used in raw salads must be fresh, tender and turgid, withno yellowing, decay, or insect or mechanical damage. Whole plants of rocket and lambs lettuce aresometimes sold with roots attached, which lengthens postharvest life.

Horticultural Maturity Indices: Greens are harvested as individual leaves, leaf clusters, or wholeplants and should be young, tender and mild flavored. Plants that have flowered are usually too strong inflavor and tough in texture for use in raw salads.

Grades, Sizes and Packaging: These crops are not graded or sized in the U.S. Salad greens may bepacked in fiberboard cartons lined with perforated polyethylene bags, small sealed plastic bags, trays orclamshell containers. These greens may also be packed as bunches of leaves or plants (Rubatzky andYamaguchi, 1997; Pron and Rees, 1998).

Pre-Cooling Conditions: Greens for salads should be cooled to 0 C (32 F) as soon as possible afterharvest. Vacuum-cooling is effective for removing field heat.

Optimum Storage Conditions: Salad greens should be stored at 0 to 2 C (32 to 36 F) with 95 to100% RH. Rocket salad typically lasts 7 to 10 days and other leafy greens 10 to 14 days (Cantwell,1997). Top icing can be used.

Controlled Atmosphere (CA) Considerations: CA is generally not beneficial. MAP is mostlybeneficial for controlling RH. However, lambs lettuce retains acceptable quality after 28 days in sealedplastic bags with reduced O2 and elevated CO2 at < 4 C (39 F) (Leiris, 1987). MAP of sorrel reducesyellowing and decay (Aharoni et al., 1993).

Retail Outlet Display Considerations: Use of water sprinklers is acceptable. Leafy greens are highlysusceptible to water loss and wilting.

Chilling Sensitivity: Salad greens are not sensitive to chilling and should be stored as cold as possiblewithout freezing.

Ethylene Production and Sensitivity: Salad greens have very low ethylene production, but are highlysensitive to ethylene exposure (Cantwell, 1997), which typically results in loss of chlorophyll leading toyellowing of leaves.

Respiration Rates:Temperature Rocket salad Lambs lettuce


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(mg CO2 kg-1 h-1)

0 C 42 125 C 113 -7 C - 6710 C - 8120 C - 139

To get mL kg-1 h-1, divide the mg kg-1 h-1 rate by 2.0 at 0 C (32 F), 1.9 at 10 C (50 F), and 1.8 at 20C (68 F). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton per day or by61 to get kcal per metric ton per day. Data are from Cantwell and Reid (1993), Cantwell (1997), Peiris etal. (1997), Rubatzky and Yamaguchi (1997), and Piergiovanni et al. (1999). Respiration rates for othergreens are not reported, but would be expected to be similar.

Physiological Disorders: Due to the delicate texture of the leaves, they are highly susceptible tomechanical damage, which may result in discoloration and decay.

Postharvest Pathology: Low temperatures must be maintained throughout the cold chain to minimizepathological disorders and prolong shelf-life. Salad greens are typically susceptible to the same bacterialsoft rot and fungal decay as lettuce.


Suitability as Fresh-cut Product: Intact leaves are sometimes included in packaged salad mixes.

Special Considerations: They must be handled carefully to avoid mechanical damage and water loss.

References:Aharoni, N., O. Dvir, D. Chalupowicz and Z. Aharon. 1993. Coping with postharvest physiology of fresh

culinary herbs. Acta Hort. 344:69-78.Cantwell, M. 1997. Properties and recommended conditions for storage of fresh fruits and vegetables.

http://postharvest.ucdavis.edu.

Cantwell, M.I. and M.S. Reid. 1993. Postharvest physiology and handling of fresh culinary herbs. J.Herbs Spices Medicinal Plants 1:83-127.

de Leiris, J. 1987. The packaging of fresh vegetables in barrier films and modified atmospheres. In: Proc.1st Intl Conf. Pack. Adv., Nova-Pack , Dusseldorf, Germany, pp. 135-162.

Peiris, K.H.S., J.L. Mallon and S. J. Kays. 1997. Respiratory rate and vital heat of some specialtyvegetables at various storage temperatures. HorTechnology 7: 46-49.

Pron, J.Y. and D.C. Rees. 1998. High-tech production of corn salad (Valerianella locusta (L.) Laterr.), alocal, French vegetable crop. Acta Hort. 467:259-268.

Piergiovanni, L., P. Fava and S. Ceriani. 1999. A simplified procedure to determine the respiration rateof minimally processed vegetables in flexible permeable packaging. Ital. J. Food Sci. 11:99-110.

Rubatzky, V.E. and M. Yamaguchi. 1997. World vegetables: principles, production and nutritive values.Chapman and Hall, London.
http://postharvest.ucdavis.edu/http://postharvest.ucdavis.edu/


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Salsify

Fabio MencarelliIstituto Tecnologie Agroalimentari, Universit della Tuscia,Via DeLellis, 01100 Viterbo, Italy

Scientific Name and Introduction: Salsify (Tragopogon porrifolius var.sativus (Gaterau) Br.-Bl.)belongs to the Compositae family. It is also called vegetable oyster and oyster plant. It is a biennial thatproduces an edible taproot. The root is light yellow outside and white inside, 15 to 30 cm (6 to 12 in)long with a diameter of 2 to 2.5 cm (0.75 to 1 in). Black salsify (Scorzonera hispanica L.) belongs to thesame family. Its taproot is larger, more cylindrical in shape, brown-black on the outside, and whiteinside. Both are rich in iron, vitamins (B1, B2, and E) and inulin, asparagin, and the glycoside laricin.Inulin is poorly digested by humans, and can be used as a bulking ingredient in foods formulated withartificial sweeteners (see Jerusalem artichoke) and as a source of fructose (Kierstan, 1978).

Quality Characteristics and Criteria: There are no U.S. or international standards. There are manyrecommendations, but they are not mandatory. Taproots must be sound, clean, fresh, and without anyforeign smell or taste. They must be full-bodied, straight and unbranched. They should not be woody.Color must be uniform, light-yellow or brown-black.

Horticultural Maturity Indices: Harvest is based on root size and time from seeding; usually after 150to 210 days.

Grades, Sizes and Packaging: No official grades exist; sizing is based on length and diameter.Package in plastic liners or trays wrapped with plastic film to minimize water loss.

Pre-cooling conditions: Pre-cooling is not necessary.

Optimum Storage Conditions: Under refrigerated conditions, salsify roots can be stored for 3 to 4 moat 0 C (32 F) with 95 to 98% RH (Hardenburg et al., 1986). In the absence of refrigeration, roots are

also commonly stored in clamps (Hak, 1993).

Controlled Atmosphere (CA) Considerations: Black salsify can be stored in 3% CO2 + 3% O2 for 6mo at 0 C (32 F) with excellent results (Stoll, 1974).

Retail Outlet Display Considerations: The skin is very delicate, and they easily lose water if they arenot in plastic lined trays. Misting with water is beneficial.

Chilling Sensitivity: Not chilling sensitive. Store as cold as possible without freezing.

Ethylene Production and Sensitivity: Produces very low ethylene and has low sensitivity to ethylene.


-1 h-1

0 C 22 to 285 C 33 to 5310 C 40 to 5720 C 193

To get mL kg-1 h-1, divide the mg kg-1 h-1 rate by 2.0 at 0 C (32 F), 1.9 at 10 C (50 F), and 1.8 at 20 C(68 F). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton per day or by 61 to


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get kcal per metric ton per day.

Physiological Disorders: Freezing is a risk during storage.

Postharvest Pathology: The most frequent diseases in the field areAlbugo tragopogonis, causing russetspotting on leaves, and powdery mildew (Erysiphe cichoriacearum DC.) which compromises quality.


Suitability as Fresh-cut Product: No current use as fresh-cut product.

References:Anonymous. 1989. Guide to food transport. Mercantila Pub., pp. 216Cantwell, M. 1997. Properties and recommended conditions for storage of fresh fruits and vegetables.

Postharvest. Univ of Calif., Davis CA.Graifenberg A. 1990. Scorzobianca. In: Orticoltura, V.V. Bianco and F. Pimpini (eds) Patron Press,

Bologna, Italy, pp. 345-349.Hak, P.S. 1983. Kuilbewaring van fabrieksaardappelen, suikerbieten, rode bieten, schorseneren en

winterpeen. Bedrijfsontwikkeling 14:799-801.Hardenburg, R.E., A.E. Watada, and C.Y. Wang. 1986. Salsify. In: USDA Hndbk. No. 66, pp. 69.Kierstan, M.P.J. 1978. Production of fructose syrups from inulin-containing plants [Jerusalem artichokes,

chicory, salsify extracts]. Biotech. Bioeng. 20:447-450.Muller-Lemans, H. 1991. Tragopogon porrifolium, die Haferwurzel-eine Literaturbersicht.

Gartenbauwissensshaft 2:53-58.Peiris, K.H.S., J.L Mallon and S.J. Kays. 1997. Respiration rate and vital heat of some specialty

vegetables at various storage temperatures. HortTechnology 7:1, 46-49Stoll, K. 1974. Storage of vegetables in modified atmospheres. Acta Hort. 38:13.


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Sapodilla and Related Fruits

Elhadi M. YahiaFacultad de Qumica, Universidad Autnoma de QuertaroQuertaro, Mxico

Note regarding respiration data for Sapodilla and related fruit:To get mL kg-1 h-1, divide the mg kg-1 h-1 rate by 2.0 at 0 C (32 F), 1.9 at 10 C (50 F), and 1.8 at 20C (68 F). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton per day or by61 to get kcal per metric ton per day.

Sapodilla

Scientific Name and Introduction: The sapodillas (Manilkaraachras (Mill) Fosb., synAchrassapota,L.) are fruit of the chicle tree, and also known as sapota, chiku, ciku, dilly, nasberry, sapodilla plum,chico zapote, zapote, chico, nspero and sapota plum. The fruit is a fleshy berry, ellipsoidal, conical or

oval, and contain one or several shiny black seeds. It weighs about 70 to 300 g, has a dull brown colorand thin skin and yellowish, light brown or red pulp. Sapodilla fruit are prized for pleasant aroma andsweet taste. Fruit growth follows a sigmoid pattern (Lakshminarayana and Subramanyam, 1966). Fruitare very susceptible to mechanical injury.

Horticultural Maturity Indices: The erratic flowering habit of sapodilla and the presence of fruit at allstages of development on the tree make it difficult to determine optimum harvest time(Lakshminarayana, 1980). Fruit harvested later than optimum time usually soften very rapidly andbecome very difficult to handle. Fruit harvested earlier than physiological maturity may not soften, areusually low in sweetness and high in astringency when ripe, with a rather unappealing alcoholicaftertaste, and form pockets of coagulated latex that lower quality. Unripe fruit are highly astringent andcontain large amounts of leucoanthocyanidins. The sucrose content and pulp-to-peel ratio increaseduring maturation (Pathak and Bhat, 1953). The fruit shed off brown scaly external material and become

smooth when reaching physiological maturity (Lakshminaryana 1980). Fruit ready for harvest will notshow a green tissue or latex when scratched with a fingernail. Fully mature fruit will have a brown skin,and fruit will separate easily from the stem without leaking latex. Extent of scurfiness is also a goodindicator of maturity (Kute and Shete, 1995). A fruit with a smooth surface, shining potato color androunded styler end is considered mature (Kute and Shete, 1995).

Grades, Sizes and Packaging: Fruit are commonly cell packed in fiberboard or wood flats with 25 to49 fruit (4.5 kg; 10 lb) per flat (McGregor, 1987).

Optimum Storage Conditions: Postharvest life is 2 to 3 weeks at 12 to 16 C (53.6 to 60.8 F) with 85to 90% RH. Storage-life is about 13 days at 25 C (77 F), 15 days at 20 C (68 F), and 22 days at 15C (59 F) (Broughton and Wong, 1979). Short-term holding of fruit for less than 10 h at 4 C (39.2 F)

before storage at 20 C (68 F) extended storage-life up to 24 days with satisfactory quality (Broughtonand Wong, 1979). Exposure of fruit to gamma irradiation at 0.1 KGy extended storage-life by 3 to 5days at 26.7 C (80 F) and 15 days at 10 C (50 F) without any effect on ascorbate content (Salunkheand Desai, 1984).

Modified and Controlled Atmosphere (CA) Considerations: Storage-life of sapodilla is extended byuse of MA and removal of ethylene (Broughton and Wong, 1979; Yahia, 1998). Storage-life at roomtemperature increased from 13 to 18 days with 5% CO2, 21 days with 10% CO2, and to 29 days with 20%CO2. However, fruit held in 20% CO2 failed to ripen, and this level of CO2 (20%) is deleterious.


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Kalpatti fruit treated with 6% Waxol or 250 or 500 ppm Bavistin, or hot water at 50 C (122 F)for 10 min, and wrapped in 150 gauge polyethylene film with 1% ventilation, ripened later than thecontrols, but fungal rot was high (Bojappa and Reddy, 1990). Fruit treated with 6% wax emulsion andpacked in 200-guage polyethylene covers containing ethylene and CO 2 absorbents had a shelf-life of 45days at 12 C (53.6 F), 10 days more than controls (Chundawat, 1991).

Jantuang fruit were successfully stored using MAP for 4 weeks at 10 C (50 F) and 3 weeks at 15

C (59 F), a week longer than fruit without MAP (Mohamed et al., 1996).

Chilling Sensitivity: Sapodilla fruit are highly susceptible to chilling injury (CI). Storage of fruit at 6to 10 C (50 F) causes irreversible damage and results in poor flavor (Broughton and Wong, 1979;Salunkhe and Desai, 1984). CI also occurred in fruit stored for 21 days at 10 C (50 F). However, fruitwaxed with a fatty acid sucrose ester kept for 40 days at 10 C (50 F).

Ethylene Production and Sensitivity: Ethylene production is 2.8, 3.7 and 6.1 L kg -1 h-1 at 15, 20 and25 C (59, 68 and 77 F), respectively (Broughton and Wong, 1979). Treatment of sapodilla fruit withetherel at 1 to 3 mL L-1 accelerated ripening, and reduced pectin content, phenolic content, SSC, sugarcontent and Vitamin C (Shanmugavelu et al., 1971; Das and Mahapatra, 1977; Ingle et al., 1982).Removal of ethylene delays ripening (Chundawat, 1991).

Respiration Rates: Sapodilla is a climacteric fruit (Broughton and Wong, 1979, Lakshminaryana andSubramanyam, 1966), but does not reach the climacteric while on the tree (Lakshminaryana andSubramanyam, 1966). The respiration rate at 24 to 28 C (75.2 to 82.4 F) was 16 mg (9 l) CO2 kg

-1 h-1

(Lakshminaryana and Subramanyam, 1966). Pre-harvest sprays of isopropyl n-phenylcarbamate (IPC) at100 L L-1 retard respiration, while maleic hydrazide at 0.5 to 1.0 mL L-1 accelerate it (Lakshminarayanaand Subramanyam, 1966).

Postharvest Pathology: Diseases and pests are rare. Phytophthorapalmivora and species ofPestalotiopsis andPhomopsis can cause fruit rot (Snowdon, 1990). Some species of bacteria areassociated with fruit latex (Pathak and Bhat, 1952).

Pests: Insects that infest sapodilla fruit includeNephopteryxengraphella Rag., fruit flies and an

unidentified borer (Kute and Shete, 1995). The most troublesome fruit flies are the Mediterranean fruitfly (Ceratitiscapitata, Wied.) and Mexican fruit fly (Anastrephaludens, Loew.).

Sapote

Scientific Name and Introduction: The sapote, zapote, mamey, mamey colorado, mamey sapote, chico-mamey, marmalade-fruit, marmalade-plum, grosse sapote (Pouteriasapota Jacq., H.E. Moore & Stearn,syn. Colocarpumsapota (Jacq., Merr., Calocarpummammosum, Pierre.,Achrasmammosa L.,Lucumamammosa, Gaertn., Vitellariamammosa, Radlk., andAchradelphamammosa, Cook) is ovoid to ellipsoidin shape, 7 to 15 cm long and 10 to 15 cm in diameter. The skin is thick and woody with a russet-brownand somewhat scurfy surface. The pulp of mature fruit is soft and smooth to finely granular in texture,

salmon pink, orange, and red or reddish-brown in color. The pulp has a sweet, almond-like flavor andlow fiber content, creamy texture and rich flavor. Fruit weigh 0.3 to 3 kg and contain a large ellipticalseed that has a shiny, hard, dark-brown surface with a light-brown hilum on the ventral side.

Quality Characteristics and Criteria: Inferior or improperly ripened mamey sapotes will develop apronounced squash-like flavor.


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Horticultural Maturity Indices and Harvesting: Fruit are harvested when the flesh begins to turn red, andmature when the newly exposed layer is turned from green to pinkish-brown, orange, or red. Immature fruitwill fail to soften, and their pulp will turn dark-brown and inedible. Harvesting must be done carefully toavoid mechanical damage. Twist the fruit until it breaks from the stem. Poles with knifes at the end are alsoused to harvest fruit. Fruit should not be allowed to fall on the ground.

Grades, Sizes and Packaging: Fruit are packed in 3 kg capacity fiberboard, flat boxes using sleeves orexcelsior (McGregor, 1987).

Optimum Storage Conditions: Storage-life is 2 to 6 weeks at 13 to 18 C (55.4 to 64.4 F) with 85 to90% RH.

Ethylene Production and Sensitivity: The fruit is climacteric and is one of the most prolific producersof ethylene at > 100 L kg-1 h-1 at 20 C (68 F) (Kader, 1992).

Physiological Disorders: Fruit are chilling sensitive. Symptoms include brown spots on the skin, poorcolor development, and development of off-flavor.

Star Apple

Scientific Name and Introduction: The star apple, caimito, sweetsop, or anon (ChrysophyllumcainitoL.) is apple-size fruit, commonly round, sometimes ovate, heart-shaped or conical, with a smooth andwaxy skin. They appear as a star when cross-sectioned. Fruit have a soft flesh, yellowish green in color,with a mild sweet flavor. The pulp is white or creamy white, with numerous embedded small, shiny,dark brown seeds.

Harvesting: Fruit should be matured on the tree, but picked before fully ripe. Fruit picked immaturewill be astringent and contain a sticky white latex. Fruit left to ripen on the tree are often split open,especially during the rainy season.

Packaging: Fruit are tray-packed in fiberboard boxes of 4.5 kg capacity (Mcgregor, 1987).

Pre-cooling: Pre-cooling should be done by hydro-cooling or forced-air.

Optimum Storage Conditions: Star apple intended for cold storage are picked at the half-ripe stage,cured in a well-ventilated room for 2 days and held at 3 to 6 C (37.4 to 42.8 F) with 90% RH for about3 weeks.

Chilling Sensitivity: Fruit are slightly sensitive to chilling injury.

Ethylene Production and sensitivity: Ethylene production at 20 C (68 F) is 10 to 100 nL kg-1 h-1. Thefruit does not respond much to treatment with ethylene (Pratt and Mendoza, 1980).

Respiration Rates: The star apple is a non-climacteric fruit. The respiration rate at 20 C (68 F) is 25to 50 mg (13 to 25 L) CO2 kg

-1 h-1. Heat evolution is 1600 to 4400 BTU per ton per day, equivalent to arespiration rate of 7 to 20 mg CO2 kg

-1 day-1 at 3 to 6 C (37.4 to 42.8 F) (Pratt and Mendoza, 1980).

Postharvest Pathology: The most important pests include the annona seed borer and the ambrosiabeetle. The annona seed borer lays eggs in the seeds of very young fruits; insects develop in the seedsand emerge as adults when the fruit matures.


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Mamey Apple

Scientific Name and Introduction: Mamey apple, also know as mamey and zapote (Mammeaamericana), is a fruit of about 300 to 500 g with a peach-like flavor, round with a thick brown leatheryskin containing one large single seed surrounded by a thin layer of yellow flesh. The fruit is a drupe

about the shape and size of an orange, with a russet surface covered with small spots. The rind is tough,about 4-mm thick, and the flesh is yellow. The endocarp is yellow, about 2- to 5-mm thick and is fusedwith the testa.

Chilling Sensitivity: Chilling injury symptoms include failure to ripen, accelerated softening,development of brown spots in pulp, and development of off-flavors and aromas.

Ethylene Production: Ethylene production at 27 C (80.6 F) is up to 400 L kg-1 h-1, among thehighest of all fruits (Akamine and Goo, 1978).

Respiration Rates: Mamey apple is a climacteric fruit. The respiration rate at 27 C (80.6 F) is 28 to40 mg (14 to 20 L) CO2 kg

-1 h-1 (Akamine and Goo, 1978).

White Sapote

Scientific Name and Introduction: White sapote or zapote blanco (Casimiroaedulis llave & Lex) isalso known as matasano in Spanish meaning killing healthy person due to the presence of the glucosidecasimirosine, mainly in seeds but also in bark and leaves. This compound has sedative effects, inducessleep, and can also calm rheumatic pains. The fruit is dull-green to greenish-yellow, subglobose to oblate,and 5 to 10 cm in diameter. The skin is very thin and the flesh is cream colored to yellowish, soft andvery sweet, with 1 to 5 large, hard, avoid seeds. The fruit is round, oval or ovoid in shape. Green-skinned varieties have white flesh and yellow-skinned varieties have yellow flesh. The skin is thin andsmooth and the flesh has a custard-like texture and sweet flavor.

Quality Characteristics and criteria: Quality fruit are yellow to yellowish green and 60 to 120 mm indiameter (McGregor, 1987).

Horticultural Maturity Indices: White sapote fruit ripen after 6 to 9 mo from bloom. Fruit color atmaturity ranges from apple-green to orange-yellow, depending on cultivar. Overripe fruit are commonlypungent with an unpleasant flavor. Fruit taste best when tree-ripened, but should be picked beforeripening. Fruit should be handled very carefully during harvesting because they are easily bruised,turning the skin black and the flesh beneath it bitter.

Optimum Storage Conditions: Storage-life is 2 to 3 weeks at 19 to 21C (66.2 to 69.8 F) with 85 to90% RH.

Postharvest Pathology: White sapote is resistant to Phytophthora and to Armillaria, but some cultivarscan be attacked by fruit flies.

Black Sapote

Scientific Name and Introduction: Black sapote (Diospyrosdignya) resembles a large, round greentomato, is 200 to 250 g, 5- to 12-cm in diameter with a thin skin, green color changing to brown or blackwhen ripe. During ripening, pulp becomes soft and black in color.


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Optimum Storage Conditions and Chilling Sensitivity: Black sapote is chilling sensitive. Fruit heldat 15, 20 or 25 C (59, 68, or 77 F) for up to 7, 10, or 15 days, and then transferred to 25 C (77 F),ripened normally (Miller et al., 1997). Fruit held at 10 C (50 F) for 7 days and then transferred to 25C (77 F) also ripened normally. However, some fruit held at 10 C (50 F) for 10 or 15 days showedabnormal ripening, and most fruit stored at 1 or 5 C (33.8 to 41 F) did not ripen normally or failed to

ripen regardless of storage duration. Black sapote will tolerate irradiation at 0.15 kGy, but abnormalripening will likely occur with some fruit when treated at 0.3 kGy (Miller et al., 1997).

Lucuma

Scientific Name and Introduction: The lucuma, lucumo, lucmo, lucma, rucma, or mamon (Lucumaobovata, HBK) is round or ovate, green on the surface, with yellow flesh and mealy texture. Fruit areabout 7 cm long. The lucuma is a climacteric fruit. It has a low water content (64 to 72%) and higheramounts of riboflavin, niacin, and ascorbate than apples or bananas (Wenkam and Miller, 1965; Lopez,1984).

Horticultural Maturity Indices: The maturity index commonly used is a change of peel color fromgreen to yellow. However, variability exists in peel and pulp color ranging from green to yellowish-green peel, and light-yellow to orange-yellow pulp (Lizana, 1980). SSC can be used as a harvest index,but fruit have a dense and dry pulp. Therefore, to measure SSC, it is necessary to disrupt pulp bymechanical means and dilute with water. If pre-mechanical disruption of cells is not undertaken,apparent SSC content will appear lower than the true value (Lizana et al., 1986).

A classification of five stages of maturity was developed according to peel and pulp color, texture,SSC and respiration (Lizana, 1980). The classes in relation to peel and pulp color are:

Class Peel color Pulp color 1 light-yellow light-yellow2 light-green creamy-yellow3 yellow-green yellow

4 green-yellow dark-yellow5 green-yellow orange-yellow

Fruit ripened on the tree usually become soft and very fragile (Lizana, 1980). The pulp of the fruitis very dry when ripe (Lizana, 1980). Intense respiratory activity and sugar accumulation occur duringripening (Lizana et al., 1986).

References:Akamine, E.K. and T. Goo. 1978. Respiration and ethylene production in Mammee apple (Mammea

americana L.). J. Amer. Soc. Hort. Sci. 103:308-310.Bojappa, K.K.M. and T.V. Reddy. 1990. Postharvest treatments to extend the shelf-life of sapota fruit.

Acta Hort. 269:391.

Broughton, W.J. and H.C. Wong. 1979. Storage conditions and ripening of chiku fruits Achras sapota L.Sci. Hort. 10:377-385.

Chundawat, B.S. 1991. Postharvest handling and marketing of sapota fruits. Natl. Sem. Opt. Prod. Util.Sapota. October 1991, Navsari, Gujarat, India.

Das, R.C. and S.K. Mahapatra. 1977. Effect of growth substances and fungicidal wax emulsion onripening of sapota. Prog. Hort. 8:75.

Ingle, G.S., D.M. Khedkar and R.S. Dabhade. 1982. Ripening studies in sapota fruit. Indian Food Packer36:72-77.

Kader, A. A. (ed). 1992. Postharvest technology of horticultural crops. Second edition, Univ. Calif., Div.


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Agric. Nat. Res., Pub. No. 3311.Kute, L.S. and M.B. Shete. 1995. Sapota (Sapodilla). In: D.K. Salunkhe and S.S. Kadam (eds) Handbook

of Fruit Science and Technology, pp. 475-484, Marcel Dekker, Inc., NY.Lakshminarayana S. 1980. Sapodilla and prickly pear. In: S. Nagy and P.E. Shaw (eds) Tropical and

Subtropical Fruits. Composition, Properties and Uses. AVI Pub, Westport CT., pp. 415-441.Lakshminarayana S. and H. Subramanyam. 1966. Physical, chemical and physiological changes in sapota

fruit (Achrassapota L.) during development and ripening. J. Sci. Food Sci. Technol. (Mysore) 3:15-154.

Lizana, L.A. 1980. Lucuma. In: S. Nagy, P.E. Shaw and W.F. Wardowski (eds) Fruits of Tropical andSubtropical Origin. Florida Science Source, Inc., Lake Alfred FL, pp. 373-380.

Lizana, L.A., G. Reginato and J.C. Lavanderos. 1986. Characterization of the maturation of the lucuma(Lucumabifera Mol., L. Obovata H.B.K.)., Proc. Interam. Soc. Trop. Hortic. 30:105-10 (InSpanish).

Lopez, C. 1984. Cultivation of the lucumo and its industrialization. Rev. Campesino 115:38-53 (InSpanish).

McGregor, B.M. 1987. Tropical products transport handbook. USDA Office Trans., Agric. Hndb. No.688.

Miller, W.R., J.L. Shari and E. Baldwin. 1997. Quality of irradiated and non-irradiated black sapote(Diospyros digyna Jacq.) after storage and ripening. Proc. Fla. State Hort. Soc. 110:215-218.

Mohamed, S., B. Taufik and M.N.A. Karim. 1996. Effects of modified atmosphere packaging on thephysiological characteristics of ciku (Arcassapota L.) at various storage temperatures. J. Sci. FoodAgric. 70:231-240.

Pathak, S. and J.V. Bhat. 1952. Studies on the microrganisms associated with Achrassapota. J. Univ.Bombay 20(5):14-18.

Pathak, S. and J.V. Bhat. 1953. The carbohydrate metabolism of Acras sapota fruit. J. Univ. Bombay21(5): 11-16, Section A.

Pratt, H.K. and D.B. Mendoza Jr. 1980. Fruit development and ripening of the star apple (Chrysophyllumcainito L.). HortScience 15:721-722.

Salunkhe, D.K. and B.B. Desai. 1984. Postharvest biotechnology of fruits. Vol. II. CRC Press, BocaRaton, Fl, pp. 387-396.

Shanmugavelu, K. G. Srinivasan and V.N.M. Rao. 1971. Influence of etherel (2-chloroethyle phosphonic

acid) on ripening of sapota (Achraszapota L.). Hortic Adv. 8:33-36.Wenkam, N.S. and C.D. Miller. 1965. Composition of Hawaii fruits. Hawaii Agric. Exp. Sta. Bull. No.

135.Yahia, E.M. 1998. Modified/controlled atmospheres for tropical fruits. Hort. Rev. 22:123-183.

Acknowledgments: Some of the information included was from the University of Florida website:http://hammock.ifas.ufl.edu/tropical_fruits.htm.
http://hammock.ifas.ufl.edu/tropical_fruits.htmhttp://hammock.ifas.ufl.edu/tropical_fruits.htmhttp://hammock.ifas.ufl.edu/tropical_fruits.htm


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Southern Pea

Penelope Perkins-Veazie1 and Blair Buckley21South Central Agricultural Laboratory, USDA, ARS, Lane, OK2Louisiana State University Research Station, Calhoun, LA

Scientific Name and Introduction: Southern pea, or cowpea, [Vigna unguiculata (L.) Walp.] is anative of Africa and is adapted to hot dry climates. The southern pea is not actually a pea, and thusdiffers considerably from the green or English pea (Pisum sativum) (Peirce, 1987). Prized in the southernU.S., southern peas are rich in folic acid, fiber, and calcium. Peas are distinguished by pod color, peacolor and pattern, and hilum color. Five groups of cultivars are recognized on the basis of seed and podcoloration, and seed packing in pod. They include Blackeye (California Blackeye No. 5), Cream(Elite), Purple Hull (Pinkeye Purple Hull), Crowder (Mississippi Silver), and miscellaneous othercolored, non-crowder peas (Dixielee). Bettersnap was developed specifically for edible pods (Feryand Dukes, 1995).

Quality Characteristics and Criteria: Some cultivars have edible pods (similar to green beans) andshould be harvested when the pods are 10 to 16 cm (4 to 6 in) long, flexible, and dark green. The shelledpeas should be a mature size, smooth skinned, and exhibit characteristic color.

Horticultural Maturity Indices: Fresh market southern peas are harvested when the pods are at themature-green stage (peas are fully developed and the majority of the pods have undergone a colorchange). It is acceptable to have some pods that have not undergone a complete color change (green withsome purpling in the case of purple hulls) provided the peas are mature size. Shelled peas preferablyshould be light green in color. Pea color is affected both by maturity and cultivar. Tan or white pea coloris perceived to be too mature (except for cream types). Blackeye cultivars are the most difficult todetermine when to harvest for fresh use because the color of the black hilum does not fully develop untilat peak maturity. The color will be purple to chocolate-brown if harvested early. If southern peas are tobe harvested for edible pod use, they must be selected when quite young and tender, ie., no more than 1/2of the expected diameter of mature green pods, unless using a cultivar specifically developed for edible

pod use.

Grades, Sizes and Packaging: USDA grades of southern peas are U.S. No. 1 (95% of pods must be atleast 12.5 cm (5 in) long, and U.S. Commercial (no minimum length requirement). Shelled peas aremarketed in 4.5 to 5.4 kg (10 to 12 lb) plastic bags (considered the equivalent amount of a shelledbushel) or in 0.45 kg (1 lb) bags. Some large operations package peas in vacuum-packed 0.45 and 4.5 kg(1 and 10 lb) bags. No grades exist for southern peas used as snap beans. Fresh southern peas may alsobe sold in the hull by the bushel. A USDA bushel is 11.4 kg (25 lbs); however, at the local market levelthe bushel weight varies widely from region to region or from 7.3 to 13.6 kg (16 to 30 lbs). Pods forshelling are packed primarily in meshed bags (cabbage sacks) or wooden bushel baskets (increasinglyless common).

Pre-cooling Conditions: In both shelled and unshelled states, peas are very prone to decay if held atroom temperature. Unshelled peas are best cooled using a forced-air system. Contact with water greatlyaccelerates their deterioration. Shelled peas should be blown free of foreign material and then hydro-cooled in 100 ppm chlorine to remove heat quickly, preserve green color, and slow microbial growth.Peas to be trucked for processing are shelled into field bins where temperatures may reach 38 C (100 F)(Hardenburg et al., 1986). Peas start to yellow and decay after a few h at 25 C (77 F). Flavordeterioration and off-flavor in shelled peas may be a problem if they are held for as much as 7 h at 30 C(86 F) before processing.


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Optimum Storage Conditions: Southern peas in the pod can be held for 6 to 8 days at 4 to 5 C (39 to41 F) with 95% RH. Without refrigeration, they remain edible only about 2 days and show extensivedecay in 4 to 6 days. Shelled peas should be held for no more than 24 to 48 h at 4 to 5 C (39 to 41 F)(Jenkins, 1954).

Controlled Atmosphere (CA) Considerations: Unknown.

Retail Outlet Display Conditions: Keep under high RH, refrigerate to slow decay and color loss.

Chilling Sensitivity: Unknown, probably sensitive when held at 5 C (41 F) or below.

Ethylene Production and Sensitivity: Unknown, probably sensitive to ethylene with effectscharacterized by yellowing of pods.

Respiration Rates:Temperature Whole pods Shelled peas

(mg CO2 kg-1 h-1)

2 C 12.5 to 36.3 25.5 to 33.35 C 15.9 to 33.4 -20 C 144.8 to 150.9 89.8 to 161.2

To get mL kg-1 h-1, divide the mg kg-1 h-1 rate by 2.0 at 0 C (32 F), 1.9 at 10 C (50 F), and 1.8 at 20C (68 F). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton per day or by61 to get kcal per metric ton per day. Data are from P. Perkins-Veazie (unpublished). Data are frompods 15 to 23 cm long, of cultivars Excel, BetterSnap, Early Scarlet, Pinkeye Purple Hull BVR. Higherrespiration values are for less mature (more green) peas and pods.

Physiological Disorders: Brown spots, cracking and seed-coat splitting are problems with pods andpeas.

Postharvest Pathology: Very little research has been done on postharvest pathogens of southern pea.

Botrytis cinerea (Gray Mold) can quickly develop on pods and shelled peas (Roland E. Roberts, TexasA&M, personal communication).Quarantine Issues: None known.

Suitability as Fresh-cut Product: Snap pea or yard-long cowpea cultivars, ex., Bettersnap, can be usedas a fresh-cut product. These types must be harvested at the immature pod stage.

Special Considerations: Failure to pre-cool shelled peas prior to packaging results in condensation inthe bags and rapid souring and spoiling of the peas. Insect damage can create major postharvest gradingproblems due to feeding damage and misshaped peas caused by stinkbugs, and punctures and larvaeinside of peas as a result of cowpea cucurlio.

References:Fery, R.L. and P.D. Dukes. 1995. Bettersnap southernpea. HortScience 30:1318-1319.Hardenburg, R.E., A.E. Watada, and C.Y. Wang. 1986. The Commercial Storage of Fruits, Vegetables,

and Florist and Nursery Stocks. USDA Agric. Hdbk No. 66, Washington, D.C.Jenkins, W.F. 1954. Postharvest changes in refrigerated and non-refrigerated southern peas. Proc. Amer.

Soc. Hort. Sci. 64:327-330.Peirce, L.C. 1987. Legumes-southern pea. In: Vegetables: characteristics, production, and marketing. J.

Wiley and Sons, NY, pp. 345-347.


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Sprouts

Jennifer R. DeEllHorticultural Research and Development CentreAgriculture and Agri-Food Canada

Saint-Jean-sur-Richelieu, Quebec, Canada

Scientific Name and Introduction: Sprouts are young seedlings just after seed germination. The mostcommon marketed sprout is Mung bean (Vigna radiata L. Wilczek; syn.,Phaseolus aureus Roxb.).Other sprouts include; alfalfa (Medicago sativa L.), buckwheat (Fagopyrum esculentum Moench), greenpea (Pisum sativum L.), kidney, pinto, and navy bean (Phaseolus vulgaris L.), lentil (Lens culinarisMedik.), mustard (Brassica nigra L. Koch; Sinapis alba L.), onion (Allium cepa L.), radish (Raphanussativus L.), red clover (Trifolium partense L.), soybean (Glycine max L. Merr.), watercress (Nasturtiumofficinale R.Br.), and Winter cress (Barbarea vulgaris R.Br.).

Quality Characteristics and Criteria: Fresh Mung bean sprouts have crisp white hypocotyls andyellow or green cotyledons. Symptoms of deterioration include; darkening of the root and cotyledons,development of dark streaks on the hypocotyl, and eventual development of sliminess, decay, and amusty odor. Other sprouts vary in texture and taste; some are spicy, eg., radish and onion, others arehardy and often used in Asian foods such as Mung bean sprouts, while others are more delicate and usedin salads and sandwiches to add texture and moistness, like alfalfa sprouts.

Horticultural Maturity Indices: Sprouts are harvested after 1 to 8 days of growth, depending on thetype, and desired plant length and width. For example, Mung bean sprouts are normally harvested after 3to 8 days when length is 1.3 to 7.6 cm (0.5 to 3 in), while alfalfa sprouts are harvested after 1 to 2 dayswhen length is 2.5 to 3.8 cm (1 to 1.5 in), and radish sprouts after 2 to 4 days when length is 1.3 to 2.5cm (0.5 to 1 in).

Grades, Sizes and Packaging: There are no established USDA quality standards for sprouts.Perforated film packaging helps maintain the quality of fresh sprouts by reducing water loss. Alfalfa

sprouts are marketed in 112 or 168 g (4 or 6 oz) containers with 12 containers per case. Mung beansprouts are marked in the same size containers and in 2.3 kg (5 lb) open flats.

Pre-cooling Conditions: Sprouts should be cooled immediately and held at 0 C (32 F). Vacuum-cooling, hydro-cooling, and forced-air cooling are common methods.

Optimum Storage Conditions: Sprouts are highly perishable and most last 5 to 10 days at 0 C (32 F)with 95 to 100% RH. Mung bean sprouts stored at 0, 2.5, 5 or 10 C (32, 36.5, 41 or 50 F) reach thelower limit of marketability after 8.5, 5.5, 4.5 and 2.5 days, respectively (Lipton et al., 1981). The shelf-life of bean sprouts held at 0 C (32 F), but exposed daily to 20 C (68 F) for 30 min can be reduced by50%. Alfalfa and radish sprouts stored at 0 C (32 F) with > 95% RH had a shelf-life of 7, and 5 to 7days, respectively (Cantwell, 1997).

Controlled Atmosphere Considerations: The shelf-life of Mung bean sprouts can be increased bystorage under MA in which O2 is reduced and CO2 is increased (Varoquaux et al., 1996). For instance,they can be held for 4 to 5 days at 8 C (46 F) in packages containing 5% O2 + 15% CO2. Darkening ofsprouts is reduced and development of sliminess is delayed.

Retail Outlet Display Considerations: Sprouts should be held close to 0 C (32 F). Do not mist.

Chilling Sensitivity: Sprouts are highly perishable and should be stored as cold as possible without


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freezing. In some cases, the cotyledons of Mung bean sprouts darken more at lower temperatures.However, due to faster deterioration at higher temperatures, storage at 0 C (32 F) is recommended.

Ethylene Production and Sensitivity: Sprouts produce little ethylene. Mung bean sprouts produce0.15, 0.05, 0.24, and 0.90 L kg -1 h-1 at 0, 2.5, 5, and 10 C (32, 37, 41 and 50 F), respectively (Liptonet al., 1981).


-1 h-1

0 C 232.5 C 295 C 4210 C 96

To get mL kg-1 h-1, divide the mg kg-1 h-1 rate by 2.0 at 0 C (32 F), 1.9 at 10 C (50 F), and 1.8 at 20C (68 F). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton per day or by61 to get kcal per metric ton per day. Data are from Lipton et al. (1981).

Physiological Disorders: Mung bean sprout hypocotyls darken with age, becoming beige to light-tan.However, some develop light-tan to rusty-brown streaks, mainly along the lower portion of the axis(Lipton et al., 1981). Such streaks may be present at harvest and are thought to arise from a group ofcells that were injured before or during germination. Darkening of the radicles and browning of thecotyledons are other changes associated with the deterioration of Mung bean sprouts. Cotyledon color inMung bean sprouts may blacken at low temperatures, and this may be a symptom of chilling injury(DeEll et al., 2000).

Postharvest Pathology: Development of decay, sliminess and musty odors are symptoms ofdeterioration.


Suitability as Fresh-cut Product: No current potential.

Special Considerations: Sprouts have been associated with human pathogenic bacteria, such asAeromonas hydrophila,Escherichia coli O157:H7,Listeria monocytogenes, Salmonella spp., andBacillus cereus (Brackett, 1999). Therefore, the importance of proper storage and handling, along withgood worker hygiene and sanitation cannot be stressed enough.

References:Brackett, R.E. 1999. Incidence, contributing factors, and control of bacterial pathogens in produce.

Postharv. Biol. Technol. 15:305-311.Cantwell, M. 1997. Properties and recommended conditions for storage of fresh fruits and vegetables.

http://postharvest.ucdavis.edu/produce/storage/prop_qs.html.DeEll, J.R., C. Vigneault, F. Favre, T. Rennie and S. Khanizadeh. 2000. Vacuum cooling and storage

temperature influence the quality of stored Mung bean sprouts. HortScience (In Press).Lipton, W.J., W.K. Asai and D.C. Fouse. 1981. Deterioration and CO2 and ethylene production of stored

Mung bean sprouts. J. Amer. Soc. Hort. Sci. 106:817-820.Varoquaux, P., G. Albagnac, C. Nguyen-The and F. Varoquaux. 1996. Modified atmosphere packaging

of fresh bean sprouts. J. Sci. Food. Agr. 70:224-230.

Acknowledgements: Some information was from the Intl. Sprout Growers Assoc. atwww.isga-sprouts.org.
http://postharvest.ucdavis.edu/produce/storage/prop_qs.htmlhttp://www.isga-sprouts.org/http://www.isga-sprouts.org/http://www.isga-sprouts.org/http://www.isga-sprouts.org/http://postharvest.ucdavis.edu/produce/storage/prop_qs.htmlhttp://www.isga-sprouts.org/http://www.isga-sprouts.org/


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Squash

T. Gregory McCollumU.S. Horticultural Research LaboratoryUSDA-ARS, Orlando, FL

Scientific Name and Introduction: Summer squash are the young fruit ofCucurbita pepo. They aremembers of the Cucurbitaceae family. There are six horticultural groups of Summer squash: cocozelle,crookneck, scallop, straightneck, vegetable marrow, and zucchini (Paris, 1986). Summer squash iscultivated throughout the world and is available year-round. Zucchini is the most widely grown andeconomically important Summer squash.

Quality Characteristics and Criteria: Tenderness and firmness are the major quality characteristics.The surface of Summer squash should be shiny; dullness is a sign of senescence. Fruit should be firmand free of physical injury. Dark green types should be entirely green; yellowish areas are a sign ofsenescence. Water loss results in a dull surface and loss of firmness.

Horticultural maturity Indices: Summer squash are harvested up to 1 week after anthesis, when theyare still shiny in appearance. Small fruit are more desirable than large fruit because their flesh and seedsare tenderer and slightly sweet.

Grades, Sizes, and Packaging: Summer squash are graded U.S. No. 1 and U.S. No. 2 (Anon., 1984).Summer squash can be harvested over a wide range of sizes (< 50 g to > 400 g; < 2 oz to > 0.9 lb).Acceptable size is a function of the type of squash and market demand. Squash may be field packeddirectly into shipping containers or transported to the packinghouse in field boxes or bulk bins forwashing and sizing before packing. Squash are packed in a variety of containers including bushelbaskets, wire-bound wooden crates and fiberboard boxes (McGregor, 1987). A plastic liner should beused in all wooden containers to prevent abrasion and retard water loss.

Pre-cooling Conditions: Room, forced-air or hydro-cooling are acceptable methods for removing field

heat from Summer squash (Lill and Read, 1982). Prompt pre-cooling after harvest reduces the rate ofwater loss and is essential for maximum postharvest life.

Optimum Storage Conditions: Summer squash are highly perishable and not suited for storage longerthan 2 weeks (Hardenburg et al., 1986). For maximum shelf-life, Summer squash should be held at 5 to10 C (41 to 50 F) with 95% RH.

Controlled Atmosphere (CA) Considerations: Storage in low O2 atmospheres appears to be of little orno value for zucchini squash (Leshuk and Saltveit, 1990; Mencarelli et al., 1983).

Retail Outlet Display Considerations: Summer squash should not be stacked more than four layersdeep and should be arranged carefully so they do not fall off the rack. The display should be refrigerated,but direct contact with ice should be avoided as it can cause physical damage as well as lead to chillinginjury.

Chilling Sensitivity: Summer squash are chilling sensitive and should not be exposed to temperatures 15% CO2 is used, is manifested as a bluingof the skin (Ke et al., 1991), whitening of inner fruit tissues (Gil et al., 1997), and fermentative off-flavors.

Postharvest Pathology: Disease is the greatest cause of postharvest loss. The most common decay isBotrytis rot, also called Gray Mold, caused byBotrytis cinerea (Ceponis et al., 1987). The disease canbegin pre-harvest, remaining as latent infections, or begin postharvest. This fungus continues to grow at0 C (32 F). However, growth is slow at this temperature. Rhizopus rot caused byRhizopus stoloniferis another important disease of strawberry. This fungus cannot grow at temperatures below 5 C (41 F).Postharvest fungicides are not used on strawberries; therefore, prompt cooling, storage at 0 C (32 F),preventing injury, and shipment at 0 C (32 F) under high CO2 are the best methods for disease control.Damaged fruit should be eliminated from baskets to prevent spread of disease to healthy berries (nesting)(Sommer et al., 1973).

Quarantine Issues: Methyl bromide fumigation is routinely used for strawberries shipped from the U.S.to Japan and Australia to prevent eliminate live insects. For California, two-spotted spider mite andwestern flower thrips are the main pests of quarantine concern for exported fruit.

Suitability as Fresh-cut Product: Strawberries are suitable, and slices have a shelf-life of about 7 daysat 2.5 C (36.5 F) and 5 days at 5 C (41 F) (Rosen and Kader, 1989; Wright and Kader, 1997).

Special Considerations: Strawberry fruit are very delicate and easily damaged. Since the harvest crewis responsible for grading, packing, and gentle handling, their training is critical to packing a qualityproduct.

References:Ceponis, M.J., R.A. Cappellini and G.W. Lightner. 1987. Disorders in sweet cherry and strawberry

shipments to the New York market, 1972-1984. Plant Dis. 71:472-475.El-Kazzaz, M.K., N.F. Sommer and R.J. Fortlage. 1983. Effect of different atmospheres on postharvest

decay and quality of fresh strawberries. Phytopathology 73:282-285.Gil, M.I., D.M. Holcroft and A.A. Kader. 1997. Changes in strawberry anthocyanins and other

polyphenols in response to carbon dioxide treatments. J. Agric. Food Chem. 45:1662-1667.Ke, D., L. Goldstein, M. OMahony and A.A. Kader. 1991. Effects of short-term exposure to low O 2 and

high CO2 atmospheres on quality attributes of strawberries. J. Food Sci. 56:50-54.Li, C. and A.A. Kader. 1989. Residual effects of controlled atmospheres on postharvest physiology and

quality of strawberries. J. Amer. Soc. Hort. Sci. 114:629-634.Mason, D.T. and W.R. Jarvis. 1970. Postharvest ripening of strawberries. Hort. Res. 10:125-132.Maxie, E.C., F. G. Mitchell, and A. Greathead. 1959. Quality study on strawberries. Calif. Agric.

13:6,15.Mitcham, E.J., C.H. Crisosto and A.A. Kader. 1996. Strawberry in Fresh Produce Facts at website

http://postharvest.ucdavis.edu.
http://postharvest.ucdavis.edu/http://postharvest.ucdavis.edu/


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Mitchell, F.G., E.J. Mitcham, J.F. Thompson and N. Welch. 1996. Handling strawberries for freshmarket. Univ. Calif., Div. Agric. Nat. Res., Pub. No. 2442.

Rosen, J.C. and A.A. Kader. 1989. Postharvest physiology and quality maintenance of sliced pear andstrawberry fruits. J. Food Sci. 54 (3):656-659.

Sommer, N.F., R.F. Fortlage, F.G. Mitchell and E.C. Maxie. 1973. Reduction of postharvest losses ofstrawberry fruits from gray mold. J. Amer. Soc. Hort. Sci. 98 (3):285-288.

Wells, J.M. and M. Uota. 1970. Germination and growth of five fungi in low-oxygen and high-carbondioxide atmospheres. Phytopathology 60:50-53.

Wright, K.P. and A.A. Kader. 1997. Effect of slicing and controlled-atmosphere storage on the ascorbatecontent and quality of strawberries and persimmons. Postharv. Biol. Technol. 10:39-48.


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Sweetcorn

Jeffrey K. BrechtHorticultural Sciences Department, University of Florida, Gainesville, FL

Scientific Name and Introduction: Sweetcorn (Zea mays L. var. rugosa Bonaf.) is an annual grass ofthe Poaceae (Grass) family. Traditional varieties aresu1 (sugary1) mutants that contain about twice thesugar (primarily sucrose) content of field corn, as well as 8- to 10-times higher water-solublepolysaccharide. The latter imparts a creamy consistency tosu1 sweetcorn. Other mutants with increasedsugar content have more recently been used, primarilysh2 (shrunken 2), which has at least double againthe sugar content ofsu1, but almost no water-soluble polysaccharide. Less commonly used issu1/se(sugary-enhancer);se modifiessu1 to also double the sugar content, but with no loss of water-solublepolysaccharide content (Wann et al., 1997). Thesh2 mutation inhibits starch biosynthesis whilese doesnot. These newer varieties are referred to as supersweet and have become the dominant type in allmajor U.S. sweetcorn production regions. The high initial sugar content, coupled with inhibited starchsynthesis insh2 varieties, doubles the potential postharvest life of sweetcorn. However, all supersweetvarieties remain extremely perishable.

Quality Characteristics and Criteria: High quality sweetcorn has uniform size and color (yellow,white or bicolor); sweet, plump, tender, well-developed kernels; fresh, tight, green husks; and is freefrom insect injury, mechanical damage, and decay. Sweetness is the most important factor in consumersatisfaction with sweetcorn (Evensen and Boyer, 1986). All sweetcorn varieties lose sweetness andaroma during storage, but the taste ofsu1 andsu1/se varieties becomes starchy whilesh2 eventually tastewatery and bland.

Horticultural Maturity Indices: Sweetcorn harvest maturity is determined by a combination of ear fill,silk drying, kernel development, kernel sweetness, and kernel tenderness. The appearance of the juice, orendosperm, is a good indicator of maturity forsu1 andse varieties, where a milky (not watery or doughy)consistency represents proper maturity, but not forsh2 varieties, which always have a watery endosperm.

Grades, Sizes and Packaging: Grades include U.S. Fancy; U.S. Fancy, Husked; U.S. No. 1; U.S. No.1, Husked; and U.S. No. 2. Grades are based primarily on maturity, freshness, and cob length, as well asfreedom from various injuries and decay. Sweetcorn is commonly handled in wire-bound wooden crates,and less commonly in waxed fiberboard cartons, or returnable plastic containers. All contain 54 to 60ears with a weight of about 19 kg (42 lb). Some is pre-packaged in polyvinylchloride (PVC) film-overwrapped trays (Aharoni et al., 1996; Risse and McDonald, 1990), with the ends of ears trimmed andhusks partially removed to expose some kernels. PVC film is highly permeable to O2 and CO2 and actsas a moisture barrier.

Pre-cooling Conditions: Sweetcorn is often > 30 C (86 F) when harvested, and rapid removal of fieldheat is critical to retard deterioration. Maximum quality is retained by pre-cooling corn to 0 C (32 F)within 1 h of harvest and holding it at 0 C (32 F) during marketing. In practice, cooling to this extentis rarely achieved. However, cooling is the first step in a good temperature management program.Sweetcorn has a high respiration rate, which results in a high rate of heat generation. Supersweetvarieties have respiration rates equal to that of traditional sweetcorn varieties and lose sugar as rapidly(Evensen and Boyer, 1986; Olsen et al., 1991), so cooling is still critical with these newer varieties.Sweetcorn should not be handled in bulk unless copiously iced, because it tends to heat throughout thepile.

Vacuum-cooling can adequately pre-cool sweetcorn, but it must be first wetted (and top-iced aftercooling) to minimize water loss from husks and kernels (Showalter, 1957; Stewart and Barger, 1960).Crated sweetcorn can be vacuum-cooled from about 30 C (86 F) to 5 C (41 F) in 30 min. Hydro-cooling by spraying, showering, or immersion in water at 0 to 3 C (32 to 5 F) is effective, although it


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takes longer than vacuum-cooling if the sweetcorn is packed. Bulk sweetcorn takes about 60 min to coolfrom 30 to 5 C (86 to 41 F) in a well-managed hydro-cooler, while crated sweetcorn takes about 80 min(Talbot et al., 1991), and few if any operators leave it in that long. Periodic monitoring of sweetcorntemperature is needed to ensure proper cooling to at least 10 C (50 F). Hydro-cooling nomographs forbulk and crated sweetcorn are available (Stewart and Couey, 1963).

After hydro-cooling, top-icing is desirable during transport or holding to continue cooling, remove

the heat of respiration, and keep the husks fresh. When pre-cooling facilities are not available, sweetcorncan be cooled with package ice and top-ice. Injection of an ice-water slurry (slush ice) into cartons wasas effective as hydro-cooling and better than vacuum-cooling in maintaining quality (Talbot et al., 1991),probably due to residual ice in the cartons since the cooling rate was slower than for the other methods.

Optimum Storage Conditions: Traditional sweetcorn varieties are seldom stored for more than a fewdays, because of the resulting serious deterioration and loss of tenderness and sweetness. The loss ofsugar is about 4-fold as rapid at 10 C (50 F) as at 0 C (32 F). At 30 C (86 F), 60% of the sugar insu1 sweetcorn can be converted to starch in a single day, while only 6% is converted at 0 C (32 F).Whilesh2 varieties lose sugar at the same rate assu1 varieties, their higher initial sugar levels keep itsweet-tasting longer. Forsh2 varieties, water loss and pericarp toughening supplant loss of sweetness inlimiting postharvest life (Brecht et al., 1990). The former is minimized by prompt cooling, trimmingflag leaves and long shanks, and maintaining high RH, usually by icing. Denting of kernels is promotedby water loss from husk leaves (Showalter, 1967). A loss of 2% moisture may result in objectionablekernel denting. Pericarp toughening can also be minimized by prompt cooling and by maintainingsweetcorn at 0 C (32 F). Under optimum storage conditions, the potential postharvest life ofsh2sweetcorn is > 2 weeks.

Controlled Atmosphere (CA) Considerations: Increased attention for CA and MAP was spurred by aninterest in marine transport to export sweetcorn from the U.S. to Europe and the Far East, which caninvolve transit times > 2 weeks. Injurious atmospheres at 1.7 C (35 F) contain < 2% O2 or > 15% CO2(Spalding et al., 1978), resulting in fermentation, off-flavors and odors. Reduced O2 and elevated CO2reduce respiration and slow sucrose loss; elevated CO2 also reduces decay and maintains green husk color(Aharoni et al., 1996; Schouten, 1993; Spalding et al., 1978).

Retail Outlet Display Considerations: Display in refrigerated cases or with ice.

Chilling Sensitivity: Sweetcorn is not chilling sensitive; store as cold as possible without freezing.

Ethylene Production and Sensitivity: Sweetcorn produces only trace ethylene, and exogenous ethyleneis not a problem, although high ethylene amounts can lead to husk yellowing given sufficient exposuretime.


-1 h-1

0 C 30 to 515 C 43 to 8310 C 90 to 12015 C 142 to 17520 C 210 to 31125 C 282 to 435

To get mL kg-1 h-1, divide the mg kg-1 h-1 rate by 2.0 at 0 C (32 F), 1.9 at 10 C (50 F), and 1.8 at 20C (68 F). To calculate heat production, multiply mg kg-1 h-1 by 220 to get BTU per ton per day or by61 to get kcal per metric ton per day. Data are from Robinson (1975), Scholz et al. (1963), and Tewfikand Scott (1954).


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Physiological Disorders: There are no significant disorders.

Postharvest Pathology: Decay is not usually a serious problem, but when present, it typically occurs onthe husk and silks. Trimming ears can promote decay development on the cut kernels and other damagedtissues mainly caused byAlternaria alternata (Fr.) Keissler,Fusarium moniliforme Sheldon, and Mucor

hiemalis Wehmer (Aharoni et al., 1996). Thus, proper sanitation and temperature management areimportant to minimize decay in trimmed sweetcorn.


Suitability as Fresh-cut Product: Fresh-cut sweetcorn kernels are extremely perishable. Theirrespiration rate is very high; several times that of intact ears. Thus, temperature control is extremelycritical if the kernels are to have acceptable shelf-life. Problems during handling can include off flavors,microbial survival/growth, and discoloration if the temperature is not maintained near 0 C (32 F).Especially troublesome is Maillard browning when the kernels are cooked. This browning is greater inkernels from more mature ears and is correlated with temperature, storage duration, and extent ofphysical damage.

Special Considerations: None.

References:Aharoni, Y., A. Copel, M. Gil and E. Fallik. 1996. Polyolefin stretch films maintain the quality of sweet

corn during storage and shelf-life. Postharv. Biol. Technol. 7:171-176.Brecht, J.K., S.A. Sargent, R.C. Hochmuth and R.S. Tervola. 1990. Postharvest quality of supersweet

(sh2) sweet corn cultivars. Proc. Fla. State Hort. Soc. 103:283-288.Evensen, K.B. and C.D. Boyer. 1986. Carbohydrate composition and sensory quality of fresh and stored

sweet corn. J. Amer. Soc. Hort. Sci. 111:734-738.Olsen, J.K., R.E. Giles and R.A. Jordan. 1991. Postharvest carbohydrate changes and sensory quality of

three sweet corn cultivars. Sci. Hort. 44:179-189.Risse, L.A. and R.E. McDonald. 1990. Quality of supersweet corn film-overwrapped in trays.

HortScience 25:322-324.Robinson, J.E., K.M. Brown, and W.G. Burton. 1975. Storage characteristics of some vegetables and soft

fruits. Ann. Appl. Biol. 81:339-408.Scholz, E.W., H.B. Johnson and W.R. Buford. 1963. Heat evolution rates of some Texas-grown fruits

and vegetables. J. Rio Grande Valley Hort. Soc. 17:170-175.Schouten, S.P. 1993. Effect of temperature and CA storage on visual quality aspects, sugars, and ethanol

content of sweet corn. In: Proc. 6th Intl. Contr. Atmos. Res. Conf. Vol. 2, June 1993, pp. 797-799.Showalter, R.K. 1957. Effect of wetting and top icing upon the quality of vacuum cooled and hydro-

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Sweetpotato

Stanley J. KaysThe University of Georgia, Department of HorticultureAthens, GA

Scientific Name and Introduction: The sweetpotato, [Ipomoea batatas (L.) Lam.], is a member of theConvolvulaceae family which is grown for its fleshy storage roots. Though a perennial, the crop isgrown as an annual. Internationally, the s

batati vaŽno

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